Semiconductor device with under-fill material below a surface of a semiconductor chip

ABSTRACT

AS conductive patterns  11 A to  11 D are formed burying in a insulating resin  10  and a conductive foil  20  is formed being half-etched, thickness of the device is made thin. As an electrode for radiation  11 D is provided, a semiconductor device superior in radiation is provided.

BACKGROUND OF THE INVENTION

1. Detailed Description of the Invention

The present invention relates to a semiconductor device and a method ofmanufacturing the same, particularly a semiconductor device radiatingheat excellently from the semiconductor device and a method formanufacturing the same.

2. Description of the Related

In recent years, use of IC package for portable equipment or small,hi-density mounting equipment progresses, and the conventional ICpackage and its concept of mounting are largely changing. These detailsare described in CSP technology, and mounting material and devicesupporting the technology—special issue of DENSHI ZAIRYO (p.22,September 1998).

FIG. 10 is a structure adopting a flexible sheet 50 as an interposerboard, a copper foil pattern 51 is put on the flexible sheet throughadhesive, and an IC chip is fixed. There is a pad for bonding 53 formedat periphery of the IC chip as the conductive pattern 51. A pad forconnecting solder ball 54 is formed through a conductive path 51B formedin one body(integrally) with the pad for bonding 53.

At backside of the pad for connecting solder ball 54, an opening 56where the flexible sheet is opened is provided, and through the opening56, a solder ball 55 is formed. The entire body is sealed with aninsulating resin 58 using the flexible sheet 50 as a board.

However the flexible sheet 50 provided below of IC chip is veryexpensive, and there are problems that cost rises, thickness of thepackage becomes thick, and weight thereof increases.

There is a problem that heat resistance from a back face of the IC chipto a back face of the package becomes large in a supporting boardbecause the supporting board comprises material other than metal. Forsaid supporting board, there is a flexible sheet, a ceramic board, or aprinted board. A heat conduction path comprising material superior inheat conduction is the thin metal wire 57, the copper foil 51, and thesolder ball 55, the above supporting board has a structure not toradiate fully at driving. Therefore there is a problem that drivingcurrent does not flow fully because of temperature rise of IC chip atdriving.

SUMMARY OF THE INVENTION

The invention is carried out in view of the above problems, and intendsto obtain a reliable semiconductor device having a small package and agood radiation characteristics.

First, the problems are solved by having a pad provided facing to abonding electrode of a semiconductor chip, an electrode for radiationprovided at an arranged area of said semiconductor, said semiconductorchip electrically connected to said pad in face down type, andunder-fill material provided on at least a lower face of saidsemiconductor chip and sealing said semiconductor chip so as to expose aback face of said pad to make in one body.

Second, the problems are solved by having a pad provided facing to abonding electrode of a semiconductor chip, an electrode for radiationprovided at an arranged area of said semiconductor, said semiconductorchip electrically connected to said pad in face down type, under-fillmaterial provided on at least a lower face of said semiconductor chip,and an insulating resin sealing said semiconductor chip so as to exposea back face of said pad and a back face of said under-fill material tomake in one body.

Third, the problems are solved by that under-fill material comes up to aside face of the semiconductor chip and fills in a trench betweenadjacent said pads and a trench between said pad and said electrode forradiation.

Fourth, the problems are solved by having a pad provided facing to abonding electrode of a semiconductor chip, an external connectionelectrode provided at a conductive path made in one body with said pad,an electrode for radiation provided surrounded by said externalconnection electrode, said semiconductor chip electrically connected tosaid pad in face down type, under-fill material provided on at least alower face of said semiconductor chip, and a insulating resin sealingsaid semiconductor chip so as to expose a back face of said externalconnection electrode and a back face of said under-fill material to makein one body.

Fifth, the problems are solved by having a pad provided facing to abonding electrode of a semiconductor chip, an external connectionelectrode provided at a conductive path made in one body with said pad,an electrode for radiation provided being surrounded by said externalconnection electrode, said semiconductor chip electrically connected tosaid pad in face down type, under-fill material provided on at least alower face of said semiconductor chip and sealing so as to expose a backface of said external connection electrode and to make in one body.

Sixth, the problems are solved by that said under-fill material comes upto a side face of the semiconductor chip and fills in a trench betweenadjacent said pads, a trench between adjacent said conductive paths, anda trench between said external connection electrode and said electrodefor radiation.

Seventh, the problems are solved by that a connection means connectingsaid semiconductor chip and said pad is brazing material, conductivepate, or anisotropic resin.

Eighth, the problems are solved by that side face of said pad comprisesa curved structure.

Ninth, the problems are solved by that side face of said pad, theconductive path made in one body with said pad, and the externalconnection electrode comprise a curved structure.

Tenth, the problems are solved by preparing a conductive foil andhalf-etching so as to form a conductive pattern in projection;

connecting said conductive pattern and a semiconductor chip in face downtype;

filling under-fill material at least between said semiconductor chip andsaid conductive;

providing a insulating resin at said conductive foil so as to seal saidsemiconductor chip and said conductive pattern; and

exposing a back face of said under-fill material and removing a backface of said conductive foil so as to separate as the conductivepattern.

Eleventh, the problems are solved by preparing a conductive foil andhalf-etching so as to form a conductive pattern in projection;

connecting said conductive pattern and a semiconductor chip in facedown;

filling under-fill material at least between said semiconductor chip andsaid conductive; and

exposing a back face of said under-fill material and removing a backface of said conductive foil so as to separate as the conductivepattern.

Twelfth, the problems are solved by that the device is separated bydicing after separating said conductive pattern.

Thirteenth, the problems are solved by that the conductive patternbecoming a unit is formed in matrix shape at said conductive foil andsaid semiconductor chip is formed at each unit.

Fourteenth, the problems are solved by that the device is separatedbetween said units by dicing after separating said conductive pattern.

By providing the semiconductor device, it is possible to transfer heatof a semiconductor chip to an electrode for radiation. As a conductivepattern including the electrode for radiation is formed without using asupporting board, it is possible to decrease cost and make thickness ofthe semiconductor chip thin.

BRIEF DESCRIPTION OF THE DRAWINGS

[FIG. 1]

FIG. 1 is a view describing the semiconductor device of the invention.

[FIG. 2]

FIG. 2 is a view describing the method for manufacturing thesemiconductor device of the invention.

[FIG. 3]

FIG. 3 is a view describing the method for manufacturing thesemiconductor device of the invention.

[FIG. 4]

FIG. 4 is a view describing the method for manufacturing thesemiconductor device of the invention.

[FIG. 5]

FIG. 5 is a view describing the method for manufacturing thesemiconductor device of the invention.

[FIG. 6]

FIG. 6 is a view describing the method for manufacturing thesemiconductor device of the invention.

[FIG. 7]

FIG. 7 is a view describing the semiconductor device of the invention.

[FIG. 8]

FIG. 8 is a view describing the conductive pattern using for thesemiconductor device of the invention.

[FIG. 9]

FIG. 9 is a view describing the semiconductor device shown in FIG. 3.

[FIG. 10]

FIG. 10 is a view describing the conventional semiconductor device.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

First mode for carrying out describing a semiconductor device.

First, a semiconductor device of the invention is described referringFIG. 1 and FIG. 2. FIG. 1A is a plan view of the semiconductor device,and FIG. 1B is a section view cut with A—A line.

In FIG. 1, the following elements are buried in a insulating resin 10:pads 11A, conductive paths 11B in one body with the pads, externalconnection electrodes 11C provided at the other ends of the conductivepaths 11B in one body with the conductive paths 11B. Further anelectrode for radiating 11D provided at one area surrounded by theconductive patterns 11A, 11B, and 11C and a semiconductor chip 12provided on the electrode for radiating 11D are buried. Thesemiconductor chip 12 is fixed to said electrode for radiating 11Dthrough under-fill material AF, and is shown with dotted line in FIG.1A.

A bonding electrode 13 of the semiconductor chip 12 and the pad 11A areelectrically connected through brazing material SD like solder,conductive paste such as Ag paste, and anisotropic conductive resinbecause the semiconductor chip 12 is mounted in face-down type.

Side face of said conductive patterns 11A to 11D is etched withnon-anisotropy, and has a curved structure because of forming with wetetching so as to generate anchor effect by the curved structure.

The structure consists of four materials: the semiconductor chip 12,plural conductive patterns 11A to 11C, the electrode for radiation 11D,under-fill material AF, and the insulating resin 10 burying them. Inarranged area of the semiconductor chip 12, said under-fill material AFis formed at a trench on and between the conductive patterns 11A to 11D,particularly the insulating resin 10 seals at a state that back face ofthe under-fill material AF filled in the trench 14 and makes a package.Said pads 11A and semiconductor chip 12 are supported by the insulatingresin 10 and the under-fill material AF.

The under-fill material AF comprises insulating material possible toinfiltrate through a narrow gap, and material spouting to side face ofthe semiconductor chip 12 is desirable. The under-fill material AF isformed thin at the back face of the semiconductor chip, and theinsulating resin 10 may seal the under-fill material AF.

On the other hand, it will be clear by the description of the method formanufacturing below (FIG. 7), the under-fill material AF is formed evento the back face of the semiconductor chip 12 and the semiconductordevice may be made omitting the insulating resin 10.

For the insulating resin, thermosetting resin such as epoxy resin andthermoplastic resin such as polyimide resin and polyphenylenesulfide areused. All kinds of resin are used if they are resins hardening using adie and covering by dipping and painting.

For the conductive patterns 11A to 11D, conductive foil of Cu as mainmaterial, conductive foil of Al as main material, Fe—Ni alloy, layeredproduct of Cu—Al, or layered product of Al—Cu—Al is used. Of course,even other material is possible to use, particularly conductive materialto etch and to evaporate by laser is desirable. Considering half-etchingability, forming ability of plating, and thermal stress, conductivematerial of Cu as main material formed by (expand with pressurizing suchas) rolling is desirable.

In the invention, the insulating resin 10 and under-fill material AF arefilled even in said trench 15 in FIG. 1B, and in FIG. 7, the under-fillmaterial AF is filled even in said trench 15. Therefore the inventionhas a characteristic to prevent remove of the conductive patterns. Bycarrying out non-anisotropic etching using dry etching or wet etchingfor etching, the side faces of pads 11A, the side face of conductivepaths 11B, the side face of the external connection electrode 11C, andthe electrode for radiation 11D are made into curved structure so as togenerate anchor effect. As the result, the structure that the conductivepatterns 11A to 11D do not remove from the package is realized.

Further the back face of the conductive patterns 11A to 11D expose atthe back face of the insulating resin 10. In FIG. 1B, although ainsulating film 16 is formed, the back face of the electrode forradiation 11D may be directly fixed with the electrode on the mountingboard omitting the insulating film 16. The structure can radiate heatgenerating from the semiconductor chip 12 to the electrode of themounting board; can prevent temperature rise of the semiconductor chip12, and can increase driving current of the semiconductor chip 12corresponding to the temperature rise. The electrode for radiation 11Dand the semiconductor chip 12 may be electrically connected.

Because the conductive patterns 11A to 11D are supported by insulatingresin 10 being sealing resin in the semiconductor device, a supportingboard is not need. This construction is a characteristic of theinvention. As described at the prior art, the conductive path of theconventional semiconductor device is supported by a supporting board(flexible sheet, printed board, or ceramic board), or supported by alead frame, the construction which is not need originally is added.However the circuit device comprises necessary minimum components anddoes not need the supporting board so that the device has acharacteristic to be thin, light, and inexpensive because of lowmaterial cost.

At the back face of the package, the conductive patterns 11A to 11Dexpose. By covering brazing material such as solder for example, at thearea, the brazing material can get wet thickly because area of theelectrode for radiation 11D is broad. Therefore brazing material of theback face of external connection electrode 11C is not wet at theelectrode of the mounting board at fixing on the mounting board, so itis assumed to become bad connection.

To solve that, a insulating film 16 is formed at the back face of thesemiconductor device 15. In FIG. 1A, circles of dotted line shown at theexternal connection electrodes and electrodes for radiation show theexternal connection electrodes 11C and electrodes for radiation 11Dexposing from the insulating film 16. That is, as the insulating film 16covers portions except the circles and size of circle portions issubstantially same size, thickness of brazing material formed here issubstantially same. This is similar as after solder printing and afterreflow. This is similar about conductive paste such as Ag, Au, Ag—Pd andso on. By the structure, bad quality of the electrical connection aresuppressed. An exposing portion 17 of the electrode for radiation 11Dmay be formed larger than exposing size of the external connectionelectrode 11C considering radiation of the semiconductor chip. As all ofthe external connection electrodes 11C are substantially same size, allarea of the external connection electrodes 11C may be exposed, and apart of the back face of the electrode for radiation 11D may be exposedfrom the insulating film 16 with substantially same size as the externalconnection electrode 11C.

By providing the insulating film 16, it is possible to extend theconductive path provided at the mounting board to the back face of thesemiconductor device. Although the conductive path provided at themounting board side is generally is arranged going around the fixed areaof said semiconductor device, forming said insulating film 16 canarrange without going around. Further as the insulating resin 10 andunder-fill material AF are projected out of a surface level of theconductive pattern, a gap is between the conductive path and theconductive pattern formed so as to prevent short.

Second mode for carrying described a method for manufacturing of asemiconductor device

The method for manufacturing shows the method for manufacturing of thesemiconductor chip shown in FIG. 1, FIG. 2 to FIG. 6 are section viewscorresponding to A—A line of FIG. 1A.

First, a conductive foil 20 is provided as FIG. 2. Thickness thereof isdesirably 10 μm to 300 μm, here rolled copper foil of 70 μm is used.Next on the front face of the conductive foil 20, a conductive film 21or a photo resist is formed as etching tolerant mask. The pattern issame pattern as the pads 11A, the conductive paths 11B, the externalconnection electrode 11C, and the electrodes for radiation 11D. In thecase of using the photo resist instead of the conductive film 21, aconductive film such as Au, Ag, or Ni is formed at a part correspondingto at least pad in the lower layer of the photo resist. This is becausesurface of Cu is easy to oxidize and bad soldering possibly occurs.These films are able to prevent oxidation of Cu and connection ofsolder. (Refer FIG. 2 about the above.)

Next, the conductive foil 20 is half-etched through said conductive film21 or photo resist. Depth of etching may be thinner than thickness ofconductive foil 20. The thinner the depth of etching, forming the finerpattern is possible.

By half-etching, conductive patterns 11A to 11D appear at surface of theconductive foil 20 in projection shape. As above-mentioned, here Cu foilformed by roll and made of Cu as main material is used for theconductive foil 20. For the conductive foil, conductive foil made of Al,conductive foil made of Fe—Ni alloy, layered product of Cu—Al, orlayered product of Al—Cu—Al may be used. Especially the layered productof Al—Cu—Al prevents bend appearing by difference of coefficient ofthermal expansion. Rolled copper foil may be used. This is becausegrowth of crystal of X axis and y axis directions is larger than Z axisand is strong in elasticity. Especially although stress added to theconductive path 11B becomes large when the conductive path 11B is formedlong, resistance to said stress is improved by using the rolled copperfoil. (Refer FIG. 3 about the above.)

Next the bonding electrode 13 and the pad 11A are arranged so as to faceeach other with face, and are fixed through brazing material forexample.

For example, the semiconductor chip 12 having solder ball is provided,and paste comprising brazing material is painted on the pad 11A.Viscosity before baking of the paste makes temporary adhesion of thesemiconductor chip 12 possible. Setting in an oven with sate oftemporary adhesion, the brazing material is melted so that thesemiconductor chip 12 and the pad are electrically connected.

On the other hand, at a part comprising a definite gap with brazingmaterial, under-fill material AF is formed. The under-fill material AFis a material which is easy to fill into a gap between the semiconductorchip 12 and the conductive pattern, and is formed to side or back faceof the semiconductor chip 12 by controlling quantity thereof. Theunder-fill material AF is selected considering adhesiveness of theinsulating resin 10 and the conductive pattern.

Therefore the under-fill material AF is provided on a trench 14 betweenthe electrode for radiation 11D and the external connection electrode11C and a trench 14 between the conductive patterns comprising the pad11A to the external connection electrode 11C and on them. Asabove-mentioned, without using supporting board, the semiconductor chipis mounted, and height of the semiconductor chip 12 is arranged low asit is mounted with face down type. Therefore thickness of the packagedescribed below is made thin. (Refer to FIG. 4 about the above.)

An insulating resin 10 is formed so as to cover the conductive patterns11A to 11D formed by half-etching, the semiconductor chip 12. For theinsulating resin, both of thermoplasticity and thermosetting propertymay be used.

Transfer molding, injection molding, dipping, or painting realizes theresin. For the resin material, thermosetting resin such as epoxy resinis realized by transfer molding and thermoplastic resin such as liquidcrystal polymer and polyphenylenesulfide is realized by injectionmolding.

In the mode for carrying out, thickness of the insulating resin isadjusted so as to cover 100 μm upper from the top portion of thesemiconductor chip 12. The thickness may be thick or thin consideringstrength of the semiconductor device.

In the injection of resin, as the conductive patterns 11A to 11D are inone body with the sheet-shape conductive foil 20, position of theconductive patterns 11A to 11D does not shift at all as long as theconductive foil 20 does not shift.

As above-mentioned, in the insulating resin 10 and the under-fillmaterial AF, the conductive patterns 11A to 11D formed as projection andthe semiconductor chip 12 are buried, and the conductive foil 20 oflower part than the projection exposes at the back face. (Refer FIG. 5about the above.)

Next, the conductive foil 20 exposing at the back face of the insulatingresin 10 is removed and the conductive patterns 11A to 11D areindividually separated.

Various methods are considered for the separating process, that is, theback face may be separated removing by etching or grinding by polishingor grinding. Both of them may be used. There is a problem that shavingsof the conductive foil 20 and bur-shape rolled metal extended thin tooutside cut into the insulating resin 10 and the under-fill material AFat grinding till the insulating resin 10 exposes for example. Thereforeseparating the conductive pattern by etching, the device is formedwithout that metal of the conductive foil 20 cuts into the insulatingresin 10 existing between the conductive pattern 11A to 11D and theunder-fill material AF. Thus short between the conductive pattern 11A to11D of fine interval is prevented.

In the case that plural units becoming the semiconductor device 15 areformed, dicing process is added after the separating process.

Although the units are separated individually using the dicing machinehere, it is possible by chocolate breaking, pressing, and cutting.

Here the insulating film 16 is formed on the conductive patterns 11A to11D exposing at the back face separated and is patterned so as toexposes the parts shown in circle of dotted line of FIG. 1A, and afterthat, it is diced to make the semiconductor device.

The solder 23 may be formed before or after dicing.

The above method for manufacturing realizes a light, thin, short, smallpackage where a semiconductor chip buried in insulating material.

FIG. 7 is an improved semiconductor device of FIG. 1 and the insulatingmaterial 10 is omitted. After painting the under-fill material AF so asto form to the back face of the semiconductor chip 12 and solidifying inprocess of FIG. 4, the device is diced omitting forming the insulatingresin 10. In FIG. 7, the back face of the semiconductor chip 12 may beexposed. The plan view of the figure is omitted, as it is same as FIG.1A.

In all modes for carrying out of the invention, a flow-prevention filmis formed so that brazing material SD does not flow. For example ofsolder, the flow-prevent film DM at a part of at least the conductivepatterns 11A to 11C as shown in FIG. 1B so as to resist flow of solder.For the flow-prevent film, bad film in wetting ability with solder, forexample, high polymer film or oxide film formed on Ni film is used.

A plan shape of the flow-prevention film is shown in FIG. 8. Theelectrode for radiation is omitted because of the figure.

Although five patterns of type A to type E are formed in FIG. 8, one ofthem is selected. In the pattern shown in type A, the flow-preventionfilm DM is provided at border of the pad 11A and the conductive path11B, and the electrical connection means is formed at substantiallyentire area of the pad 11A. The flow-prevention film DM may be formed onan entire area of a conductive path 11B or including the externalconnection electrode 11C. In type B, the flow-prevention film DM isformed on the pad 11A, and in a part where the electrical connectionmeans is provided, the flow-prevention film DM is removed. In type C,adding to the formed area of type B, the flow-prevention film DM isformed on the conductive path 11B and the external connection electrode11C. In type D, an opening of the type C is changed to circle fromrectangle, in comparison with type C. In type E, the flow-preventionfilm DM is formed on the pad so as to be a ring shape. Although pat A isshown in rectangle, it may be circle. The flow-prevention film DMprevents flow of brazing material such as solder, conductive paste suchas Ag paste, and conductive resin, and these electrical connection meansconsist of bad material in wetting. For example, in case that solder isprovided at type D, when the solder melts, the solder is dammed withflow-prevention film DM so as to form fine hemisphere by surfacetension. Because passivation film is formed at periphery of the bondingelectrode 13 of the semiconductor chip where the solder is attached,only the bonding electrode gets wet. Therefore by connecting thesemiconductor chip and the pad through solder, the both are fixed inadductor shape keeping definite height. As size of the exposing portionand height thereof are possible to adjust by volume of solder providedthereon, a definite gap is provided between the semiconductor chip andthe conductive pattern. Therefore it is possible to fill washing liquidinto the gap. It is possible to fill adhesive low in viscosity such asunder-fill material AF. By covering all area except connecting area withthe flow-prevention film DM, it is possible to improve adhesiveness withunder-fill material AF.

Next, effect generating by the above method for manufacturing isdescribed.

First, as the conductive pattern is half-etched and supported in onebody of the conductive foil, a board used for supporting past isremoved.

Second, as the pad half-etched to make projection is formed on theconductive foil, it is possible to make the pad fine. Therefore it ispossible to make width and gap of the pad so as to form a small packagein plan size.

Third, as the device consists of necessary minimum components: theconductive pattern, the semiconductor chip, the connection means, andsealing material, useless material is removed so as to realize thinsemiconductor device extremely depressing cost.

Fourth, as the pads are formed becoming projection by half-etching andindividually separated after sealing, tie bar and hanging lead are notneed. Therefore forming and cutting tie bar (hanging lead) is not needat all in the invention.

Fifth, as the conductive foil is removed from the back face of theinsulating resin after the conductive pattern becoming the projection isburied in the insulating resin and is separated, bur of resin generatingbetween leads as the conventional lead frame is removed.

Sixth, as the semiconductor is fixed to the electrode for radiationthrough the under-fill material and the electrode for radiation exposesfrom the back face thereof, heat generating from the semiconductordevice is efficiently radiated from the back face thereof. By mixing theinsulating adhesion means with filler such as Si oxide film and aluminumoxide, radiation of the device is more improved. By unifying diameter ofthe filler, it is possible to uniform a gap between the semiconductorchip 12 and the conductive pattern.

Third mode for carrying out describing a semiconductor device.

FIG. 9 shows the semiconductor device 40. FIG. 9A is a plan view of thedevice, and FIG. 9B is a section view cut by A—A line.

Although the pad 11A is formed in one body with the conductive path 11Band the external connection electrode 11C in FIG. 1, here the back faceof the pad 11A becomes the external connection electrode.

As the back face of the pad 11A is formed in rectangle, the patternexposing from the insulating film 16 is formed in same pattern as saidrectangle. The grooves 43 are formed so that the electrode for radiation11D is divided to plural considering adhesion with the under-fillmaterial AF.

As clear from the above description, the invention has a reliableconstruction without a supporting substrate, since the conductive foilwhere the conductive pattern formed in island shape has certainthickness (or the conductive foil) is buried by the insulatingconnection means and the insulating resin. AS the electrode forradiation positioning at the back face of the semiconductor chipexposes, radiation of the semiconductor chip is removed. Further as thesupporting board is not used, a thin and light package is realized.

The device consists of necessary minimum components of the conductivepattern, the semiconductor chip, and the insulating resin, and becomes acircuit device useless for resources. Therefore there is not any extracomponents till completion so as to realize a semiconductor devicedecreasing cost extremely.

1. A semiconductor device comprising: a semiconductor chip havingbonding electrodes; a plurality of pads, each pad facing a respectivebonding electrode of the semiconductor chip, the semiconductor chipcoupled in a face down position to the pads; an under-fill materialprovided at least below a lower face of the semiconductor chip; aninsulating resin disposed over an entire upper surface of thesemiconductor chip and sealing the semiconductor chip such that theinsulating resin covers at least part of the under-fill material; and atrench between adjacent pads that extends lower than a bottom surface ofthe pads.
 2. A semiconductor device according to claim 1, furthercomprising: a conductive path integrally connected with a respectivepad; and an external connection electrode provided to the conductivepath, wherein the under-fill material is provided at least at a lowerface of said semiconductor chip while exposing a back face of saidexternal connection electrode.
 3. A semiconductor device according toclaim 1, further comprising: a connection means connecting saidsemiconductor chip, and each of said pads being a brazing material,conductive paste, or anisotropic resin.
 4. A semiconductor deviceaccording to claim 1, wherein a side face of said pads comprises acurved structure.
 5. A semiconductor device according to claim 1,further comprising an electrode for heat radiation provided below saidsemiconductor chip, wherein said under-fill material is at least betweenthe lower face of said semiconductor chip and the electrodes and besidethe electrodes.
 6. A semiconductor device according to claim 5, whereinsaid under-fill material comes up to a side face of the semiconductorchip and fills in a trench between adjacent pads and a trench betweensaid pad facing the bonding electrode and said electrode for heatradiation.
 7. A semiconductor device according to claim 5, furthercomprising: a conductive path integrally connected with said pad; anexternal connection electrode provided to the conductive path, theexternal connection electrode surrounding the electrode for heatradiation, wherein said insulating resin seals said semiconductor chip,while exposing a back face of said external connection electrode and aback face of said under-fill material.
 8. A semiconductor deviceaccording to claim 7, wherein said under-fill material comes up to aside face of the semiconductor chip and fills in a trench betweenadjacent said pads, a trench between adjacent said conductive paths, anda trench between said external connection electrode and said electrodefor heat radiation.
 9. A semiconductor device according to claim 3,wherein a side face of said pad, the conductive path integrallyconnected with said pad, and the external connection electrode have acurved structure.
 10. A semiconductor device according to claim 1,wherein the insulating resin is disposed over and seals saidsemiconductor chip while leaving a back face of said pads and a backface of said under-fill material without the insulating resin.
 11. Thesemiconductor device of claim 1 wherein the trench is filled with theunder-fill material.
 12. The semiconductor device of claim 1 wherein abottom surface of the semiconductor chip device is covered by aninsulating film with openings, each of which has substantially the sameshape, and wherein the pads are exposed from the openings.
 13. Thesemiconductor device of claim 1 wherein the under-fill material isformed separately from the insulating resin.
 14. A semiconductor devicecomprising: a semiconductor chip oriented in a face-down position andhaving electrical contacts on a bottom face adapted for coupling toconductive paths; a heat radiating pad separated by a gap from thesemiconductor chip bottom face and electrically separated from theconductive paths by a trench that extends lower than a bottom surface ofthe heat radiating pad and a bottom surface of the conductive paths, andan under-fill material provided at least below the lower face of thesemiconductor chip and filling the gap, wherein the under-fill materialsupports the semiconductor chip, the heat radiating pad and thesemiconductor chip.
 15. The semiconductor device of claim 14, wherein aninsulating resin is disposed over an entire upper surface of thesemiconductor chip and seals the semiconductor chip.
 16. A semiconductordevice comprising: a semiconductor chip oriented in a face-down positionand having electrical contacts on a bottom face adapted for coupling toconductive paths; a heat radiating pad separated by a gap from thesemiconductor chip bottom face and electrically separated from theconductive paths; a trench that extends lower than a lower surface ofthe heat radiating pad; an under-fill material provided at least belowthe lower face of the semiconductor chip and filling the both the gapand the trench; an insulating resin on an entire upper surface of thesemiconductor chip and sealing the semiconductor chip, wherein theunder-fill material fills the trenches and the gap between the lowerface of the semiconductor chip and an upper surface of the heatradiating electrode.